The present invention is directed generally to the field of surface coverings. In particular, the present invention is directed to a preglued underlayment assembly suitable for use with a decorative floor covering.
Surface coverings, particularly decorative finished flooring products, often require an underlayment to be installed over a structural wood subfloor or other substrate. Commonly, the underlayment is attached to the substrate by application of an adhesive, nails, screws, staples or any combination thereof. The underlayment serves as a foundation for the application of the surface coverings, and provides a clean, smooth surface upon which to lay the surface coverings. A smooth surface is desirable the so that the substrate""s texture or graining is not transmitted through to the viewable surface of the surface covering. Underlayments also should resist dents and punctures from concentrated loads and traffic, and should not contain substances that can stain the surface covering.
In one such type of application, a liquid adhesive is applied to the exposed surface of the underlayment, and then the surface covering is laid over the adhesive which adheres the surface covering to the underlayment. Typically, the adhesives are applied at the installation location by employing a notched trowel to spread the adhesive on the underlayment, which is a labor intensive and often messy process. Roll-on and spray-on adhesives may be employed as well. Such adhesives should firmly bond the surface covering to the underlayment to prevent the surface covering from buckling or curling through a wide range of wear and environmental conditions. Importantly, the adhesive should not contribute to staining of the finished flooring. Further, in conventional on-location adhesive application, the selected adhesive should have certain attributes or properties which make it easy to trowel and provide adequate working time over a wide variety of substrates or underlayments in combination with a wide variety of surface covering backing materials. It is known, however, that such liquid adhesives utilized at the surface covering installation site sometimes have problems with mildew staining, bottom-up staining from the substrate or underlayment, seam contamination, and vapor bubbles.
Another current practice is to provide an adhesive layer on the back of the surface covering itself. Pre-applied adhesives primarily have been utilized for carpet installation. For example, one installation device includes a thin scrim webbing with adhesive on both sides and a release film disposed over the adhesive on one side. Another similar device is a carpet padding which has a pressure sensitive adhesive on both sides and a release film disposed over the adhesive on one side. The exposed adhesive is contacted with the subfloor, and the release film is removed to expose an adhesive layer which receives and bonds to the carpet. These devices, however, are not appropriate for adhering surface coverings such as vinyl flooring to the subfloor. In the case of the scrim device, it is too varied in thickness, which allows its surface texture to show through the vinyl surface covering. Additionally, breakage can occur over its individual strands when thin, smooth, and glossy surface coverings are installed over them. The carpet installation device is likewise unacceptable for vinyl flooring installation, because it provides too much cushioning and not enough resiliency to protect surface coverings, such as vinyl sheet, tile, and veneers and high pressure laminate flooring, from indent or deflection-type damage from concentrated loads. For example, U.S. Pat. Nos. 4,557,774, 5,160,770, and 5,304,268 all to Hoopengardner disclose a carpet pad with pressure sensitive adhesive and a removable release film.
Surface coverings also are known which have a pressure sensitive adhesive layer disposed on the back side or backing material. A protective covering of a releasable film, such as a release paper or a thermoplastic or polyethylene film, is disposed over the adhesive layer. During installation, the releasable film is removed and the surface covering is pressed onto the substrate or underlayment. These surface coverings are produced by applying the releasable film to the adhesive layer by attaching the leading ends of the film and the surface covering to a core roll. The surface covering is oriented such that the adhesive layer faces inwardly towards the core roll and adjacent the protective layer. The core roll then is rotated such that the protective layer is applied to and overlies the adhesive surface as the surface covering is simultaneously collected on the core roll. Self-adhering tile, in which adhesive and release film are on the back of the tile, are prevalent in the residential flooring segment. Also, as indicated above, some manufacturers have introduced self-adhering sheet flooring (roll goods such as carpet and vinyl). This concept, however, usually involves the application of both adhesive and release film to the back of the sheet flooring by the installer. Factory applied adhesive to sheet goods presents a unique set of concerns to manufacturers of conventional flooring products due to manufacturing, logistical, packaging and storage issues.
U.S. Pat. No. 4,397,906 to Nakagawa et al. discloses a multilayer backing material consisting of a polyolefin or polybutadiene foam sheet base layer, a dry coated interlayer of polychloroprene-type adhesive, and a dry coated layer of a mixture of a water-based adhesive and an inorganic filler. The interlayer and dry coated layer can be disposed on one or both sides of the backing material. The dry coated adhesive layers allow use of water-based adhesives to adhere the backing material on one side to wall paper or a non woven fabric and the other side to a floor, wall, or ceiling.
Despite the existing methods of adhering a surface covering to an underlayment, the need for a preglued underlayment assembly that provides a smooth, indent resistant surface for the installation of surface coverings remains. Further, there remains a need for a preglued underlayment assembly which has a pre-applied adhesive layer suitable for bonding a variety of surface coverings, such as finished flooring products, and a release film or paper disposed on the preglued surface. Still further, there remains a need for a method of installing a preglued underlayment assembly over a subfloor system typically found in residential building construction, that employs staples or other like mechanical fasteners. Finally, there remains a need for a method of installing a surface covering onto a preglued underlayment assembly. It is to the provision of a preglued underlayment assembly and associated flooring installation system that meets these needs that the present invention is primarily directed.
Briefly described, a preglued underlayment assembly of the present invention comprises a substantially rigid underlayment having an upper and a lower surface, a pressure sensitive adhesive layer disposed on the upper surface, and a release sheet disposed on the adhesive layer. Another pressure sensitive adhesive layer and another release sheet are optionally provided on the lower surface of the preglued underlayment assembly. One or more performance enhancing layers, such as foam and solid layers, are disposed between the underlayment and the adhesive layer to modify and/or enhance various properties of the preglued underlayment assembly. Mechanical fasteners, such as staples, penetrate the preglued underlayment assembly and engage a structural support member, such as a subfloor, to attach the preglued underlayment assembly thereto.
Another aspect of the present invention relates to a method of installing a surface covering over a structural support member. The method includes providing at least one preglued underlayment assembly made in accordance with the present invention, positioning the at least one preglued underlayment assembly on the structural support member, fastening the at least one preglued underlayment assembly to the structural support member, removing the release sheet from the at least one preglued underlayment assembly, and placing the surface covering onto the adhesive layer of the at least one preglued underlayment assembly. The surface covering may be pressed against the underlaymnent during installation. The preglued underlayment assembly is fastened to the structural support member by the mechanical fasteners. Each mechanical fastener preferably has a crown and the crown is recessed within the preglued underlayment assembly such that the crown is substantially below the surface covering/adhesive interface to provide a substantially protrusion free surface covering.